Internet DRAFT - draft-sun-v6ops-xlat-multi
draft-sun-v6ops-xlat-multi
Network Working Group Q. Sun
Internet-Draft Z. Zhang
Intended status: Informational China Telecom
Expires: December 27, 2015 Q. Zhao
Beijing University of Posts and Telecommunications
S. Jiang
Huawei Technologies Co., Ltd
X. Lee
Y. Fu
CNNIC
June 25, 2015
Running Multiple PLATs in 464XLAT
draft-sun-v6ops-xlat-multi-02
Abstract
The IPv6 transition has been an ongoing process throughout the world
due to the exhaustion of the IPv4 address space. The 464XLAT
[RFC6877] provides a solution with limited IPv4 connectivity across
an IPv6-only network, and the android system (version 2.3 and above)
has already implemented the 464XLAT and the Prefix discovery solution
[RFC7050]. However, the current 464XLAT architecture can only deal
with the scenario with single PLAT in the network. When operator
deploys multiple PLATs with different Pref64 prefixes, 464XLAT cannot
cope with multiple prefixes for different destination addresses.
This document describes the architecture with multiple PLATs and also
the deployment considerations.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 27, 2015.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirement of Multiple PLATs in 464XLAT . . . . . . . . . . 3
4. Overall Architecture of multiPLATs in 464XLAT . . . . . . . . 4
4.1. Prefix Management Server . . . . . . . . . . . . . . . . 4
4.2. Enhanced CLAT for multiPLAT . . . . . . . . . . . . . . . 5
5. Deployment Considerations . . . . . . . . . . . . . . . . . . 6
5.1. Prefix Management . . . . . . . . . . . . . . . . . . . . 6
5.2. DNS64 Consistency . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The exhaustion of the IPv4 address space has been a practical problem
that providers are facing today. Network address migration to IPv6
is ongoing or upcoming throughout the world. The 464XLAT
architecture uses the IPv4/IPv6 translation technology standardized
in [RFC6145] and [RFC6146]. It encourages the IPv6 transition by
making IPv4 service reachable across IPv6-only networks and providing
IPv6 and IPv4 connectivity to IPv4 or IPv6 servers and peers of
single-stack. The android system (version 4.3 and above) has already
implemented the 464XLAT [RFC6877] and the Prefix discovery method in
[RFC7050].
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However, as described in section 6.3 [RFC6877], the CLAT will use the
PLAT-side translation IPv6 prefix as the destination of all
translation packets that require stateful translation to the IPv4
Internet. The Prefix Discovery method [RFC7050] cannot deal with the
scenario when different PLATs are using with different Pref64
prefixes.
This document describes the solution of 464XLAT architecture with
multiple PLATs and some deployment considerations
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
This document use the terminologies defined in [RFC6877] and
[RFC7050].
3. Requirement of Multiple PLATs in 464XLAT
As defined in [RFC6147], it allows the implementations of DNS64 to be
able to map specific IPv4 address ranges to separate Pref64::/n
prefixes. That allows handling with special use of IPv4 addresses
[RFC6890]. Therefore, operator may deploy multiple NAT64s (PLATs in
464XLAT) for different ranges of IPv4 servers. For example, one PLAT
"A" is used when accessing IPv4-only servers in the data center, and
a different PLAT "B" is used for Internet access as described in
Figure 1. These two PLATs may have implemented different ALG types
and different QoS treatment.
PLAT "A" ----- IPv4-only servers in a data center
/
IPv6-only node---<
\
PLAT "B" ----- IPv4 Internet
Figure 1: Use case of MultiPLAT
In this use case, one end user would use multiple Pref64 prefixes for
different destinations.
Another use case to deploy multiple PLATs is for load balancing. For
example, PLAT "A" would serve approximately half of the subscribers
in one network, while PLAT "B" would serve the other half as
described in Figure 2.
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PLAT "A" ----- half of the subscribers
/
IPv6-only node---<
\
PLAT "B" ----- the other half of the subscribers
Figure 2: Use case of MultiPLAT for load balancing
In this use case, one end user would still get one Pref64 for all
destinations, but it still needs a management system to allocate
different Pref64 prefixes for different users.
4. Overall Architecture of multiPLATs in 464XLAT
The overall architecture of multiPLATs in 464XLAT is depicted as
Figure 3. It consists of a Prefix Management Server, enhanced CLAT,
and multiple PLATs. The PLAT in this architecture has no difference
between the one in 464XLAT in [RFC6877].
+-----------------+
+----|Pref Mangt Server|
| +-----------------+
| +------+
+------+ | +-----+ / \
| CLAT |------+------+PLAT1+----| network1 |
+------+ | +-----+ \ /
| +------+
| +------+
| +-----+ / \
+------+PLAT2+----| network2 |
+-----+ \ /
+------+
Figure 3: Architecture of multiPLATs in 464XLAT
4.1. Prefix Management Server
The Prefix Management Server includes the following modulars as
described in Figure 4.
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+---------------------------------------------+
| +---------------+ +-----------------+ |
| |Pref64 Magt | |v4addrRange Magt | |
| +---------------+ +-----------------+ |
| +---------------+ +-----------------+ |
| |IPv6Pref Magt | | Prefix Discovery| |
| +---------------+ +-----------------+ |
| +----------------------+ |
| |Policy Configuration | |
| +----------------------+ |
+---------------------------------------------+
Figure 4: The implementation modulat of Prefix Management Server
It would be configured with the policy to allocate multiple Pref64s.
There may be different policies to apply. For example, it may map
specific IPv4 destination address ranges to separate Pref64 prefixes,
or map specific IPv6 source address ranges to separate Pref64
prefixes, or map both destination IPv4 address and source IPv6
address to Pref64 prefixes. The policy in Prefix Management Server
should be consistent with the one of the PLAT deployment.
The prefix discovery method should be able to cope with multiple
Pref64 prefixes. It may implement PCP based prefix discovery method
[RFC7225] to allocate multiple Pref64 prefixes.
4.2. Enhanced CLAT for multiPLAT
In addition to satisfy the requirements of existing CLAT, the
enhanced CLAT for multiPLAT should also implement the following
modulars as described in figure 5:
+---------------------------------------------+
| +---------------+ +-----------------+ |
| |Pref64 Magt | |v4addrRange Magt | |
| +---------------+ +-----------------+ |
| +-----------------+ |
| | Prefix Discovery| |
| +-----------------+ |
+---------------------------------------------+
Figure 5: The implementation modulars of enhanced CLAT
The prefix discovery method should be consistent with the one in the
Prefix Management Server. The Pref64 Management modular will extract
the multiple Pref64 prefixes from the prefix discovery procedure and
the v4addrRange Management modular will store the corresponding IPv4
address ranges. The prefix discovery method will get multiple Pref64
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prefixes after the process of authentication and IPv6 address
allocation. Then, the CLAT will use the Pref64 prefix as the
destination for specific IPv4 address ranges.
The translation and DNS modular is the same with the traditional XLAT
in [RFC6877].
5. Deployment Considerations
5.1. Prefix Management
The prefix management modular is important for multiPLATs in 464XLAT.
However, since it would compare the destination address range with
each packet in CLAT, it might affect the performance efficiency of
the client. So, operators should limit the number of address ranges,
and aggregate the addresses into a larger address range.
Besides, there might also be a maximum limit configured in CLAT on
the number of Pref64 prefixes and the number of address ranges. When
the number of address ranges exceeds the limit, the CLAT may ignore
the next Pref64 prefixes and use a default prefix for the rest of
destinations. However, this may cause issues for unexpected results.
5.2. DNS64 Consistency
464XLAT does not require DNS64 [RFC6147] when IPv4 host sends IPv4
packets to reach IPv4 servers. But 464XLAT networks may use DNS64 to
enable single stateful translation [RFC6146]. In this case, the
configuration policy in DNS64 should be consistent with the Prefix
Management Server. For example, how to map different IPv4 address
ranges to Pref64 prefixes and IPv6 prefixes for Preference prefixes.
6. IANA Considerations
This document has no IANA actions.
7. Security Considerations
TO BE COMPLETED
8. Acknowledgements
The authors would like to thank the following individuals who have
participated in the drafting, review, and discussion of this memo: TO
BE COMPLETED
This document was produced using the xml2rfc tool [RFC2629].
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9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, April 2011.
[RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van
Beijnum, "DNS64: DNS Extensions for Network Address
Translation from IPv6 Clients to IPv4 Servers", RFC 6147,
April 2011.
[RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT:
Combination of Stateful and Stateless Translation", RFC
6877, April 2013.
[RFC7050] Savolainen, T., Korhonen, J., and D. Wing, "Discovery of
the IPv6 Prefix Used for IPv6 Address Synthesis", RFC
7050, November 2013.
9.2. Informative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC6890] Cotton, M., Vegoda, L., Bonica, R., and B. Haberman,
"Special-Purpose IP Address Registries", BCP 153, RFC
6890, April 2013.
[RFC7225] Boucadair, M., "Discovering NAT64 IPv6 Prefixes Using the
Port Control Protocol (PCP)", RFC 7225, May 2014.
Authors' Addresses
Qiong Sun
China Telecom
No.118 Xizhimennei Street, Xicheng District
Beijing 100035
P.R. China
Email: sunqiong@ctbri.com.cn
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Zhirong Zhang
China Telecom
No.118 Xizhimennei Street, Xicheng District
Beijing 100035
P.R. China
Email: zhangzhr@ctbri.com.cn
Qin Zhao
Beijing University of Posts and Telecommunications
Beijing 100876
P.R. China
Email: zhaoq@bupt.edu.cn
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: jiangsheng@huawei.com
Xiaodong Lee
CNNIC
No.4 South 4th Street, Zhongguancun
Hai-Dian District, Beijing, 100190
P.R. China
Email: xl@cnnic.cn
Yu Fu
CNNIC
No.4 South 4th Street, Zhongguancun
Hai-Dian District, Beijing, 100190
P.R. China
Email: fuyu@cnnic.cn
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